Long-life double-agent copper etching liquid

Abstract

The invention belongs to the technical field of electronic chemicals, and particularly discloses a long-life double-agent copper etching solution which comprises a solution A and a solution B, the liquid A comprises the following components in percentage by mass: 1-6% of copper salt, 1-12% of acid, 1-20% of organic alkali, 0.01-5% of a surfactant and the balance of water; and compared with the solution A, the solution B only replaces the copper salt with the organic acid with the corresponding molar content, other raw materials are consistent, and organic alkali is added to adjust the pH to 6.2-6.8. According to the double-dosage-form copper etching solution containing the solution A and the solution B, the etching life of the solution A is continuously updated by adding the solution B, the service life of the etching solution is prolonged, and redundant technological processes are reduced, so that the production cost is saved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a long-life dual-dosage copper etching solution. Background Art

[0002] Metal interconnects in semiconductor manufacturing, advanced packaging, and display panels are generally formed by etching the photoresist pattern after the mask pattern is developed using the corresponding copper etching solution. Currently, the most commonly used copper etching solution in semiconductor manufacturing, advanced packaging, and display panels is the hydrogen peroxide series single-dose copper etching solution. However, hydrogen peroxide is easy to decompose to produce flammable gas oxygen, and it is accompanied by a large amount of heat during decomposition, which can easily cause accidents such as combustion or even explosion. The single-dose solution also needs to be replaced during use, which is not conducive to the company's safe production and continuous production. At the same time, the hydrogen peroxide series etching solution has a short service life and a high production cost. Therefore, it is very important to develop a safe, stable, efficient, and long-etching dual-dose copper etching solution.

[0003] In order to formulate a dual-type copper etching solution with high safety, stability and service life, and to make the copper etching solution adapt to the development of semiconductor manufacturing, advanced packaging and display industries and meet process requirements, it is urgent to develop a safe, efficient and long-life dual-type copper etching solution. Summary of the invention

[0004] The invention provides a long-life dual-type copper etching solution. The dual-type copper etching solution containing liquid A and liquid B is provided, and the etching life of liquid A is continuously updated by adding liquid B, thereby extending the service life of the etching solution, reducing redundant process flows, thereby saving production costs and improving production efficiency.

[0005] The technical solution of the present invention is to provide a long-life dual-type copper etching solution, which includes a solution A and a solution B; Liquid A contains the following ingredients by mass percentage: 1-6% copper salt, 1-12% acid, 1-20% organic base and 0.01-5% surfactant, the balance being water; Compared with solution A, solution B only replaces copper salt with organic acid of corresponding molar content, and the other raw materials are the same, and an organic base is added to adjust the pH to 6.2-6.8; During the etching process, only liquid A is used first. When the etching life of liquid A reaches its limit, liquid B is repeatedly added to extend its etching life.

[0006] Furthermore, the copper salt is a combination of an inorganic copper salt and an organic copper salt in a mass ratio of 1-5:1; the inorganic copper salt is one or more of copper chloride, copper sulfate and copper nitrate; the organic copper salt is one or more of copper oxalate, copper tartrate and copper glycinate.

[0007] Furthermore, the acid is a combination of an inorganic acid and an organic acid in a mass ratio of 1 to 4:1; wherein the inorganic acid is one or more of nitric acid, hypochlorous acid and sulfuric acid, and the organic acid is one or more of acetic acid, malonic acid and succinic acid.

[0008] Furthermore, the organic base is a combination of a pyrazole compound and an amino alcohol compound in a mass ratio of 1 to 4:1.

[0009] Furthermore, the pyrazole compound is one or more of 3-nitropyrazole, 1,5-dimethylpyrazole, and 3-amino-5-hydroxypyrazole.

[0010] Furthermore, the amino alcohol compound is one or more of 1-amino-2-butanol, 4-dimethylamino-1-butanol and 4-amino-2-methyl-1-butanol.

[0011] Furthermore, the surfactant is one or more of sodium lauryl polyoxyethylene ether sulfate, tetraethylammonium hydrogen sulfate and tromethamine dodecyl sulfate.

[0012] Furthermore, the organic acid is oxalic acid, tartaric acid and / or glycine corresponding to the copper salt.

[0013] Furthermore, after the Cu ion concentration of solution A reaches 18000 ppm, solution B is added to adjust the Cu ion concentration in the copper etching solution to 16000-18000 ppm.

[0014] The present invention has the following beneficial effects: The copper etching solution of the present invention is composed of a solution A and a solution B, wherein the solution A is composed of a copper salt, an inorganic acid, an organic acid, a surfactant, an organic base and deionized water, and the solution B is composed of an organic acid, an inorganic acid, a surfactant, an organic base and deionized water. In the process of etching copper and its alloys by using the etching solution, after the etching life of the solution A reaches a limit, the solution B can be added to continuously update the etching life of the solution A, thereby extending the service life of the etching solution, reducing redundant process flows, thereby saving production costs and improving production efficiency.

[0015] The acid in the present invention adopts a combination of organic acid and inorganic acid, which can increase the solubility of copper in the etching solution, better prolong the service life of the etching solution, and improve the etching uniformity; the surfactant can adopt tetraethylammonium hydrogen sulfate and the like, which can adjust the physical properties of the etching solution such as the surface tension, thereby improving the etching uniformity, prolonging the etching service life, and improving the product yield. DETAILED DESCRIPTION

[0016] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0017] A long-life dual-agent copper etching solution, the etching solution comprises liquid A and liquid B, during the etching process, only liquid A is used first, and when the etching life of liquid A reaches a limit, liquid B is repeatedly added to extend its etching life; Liquid A contains the following ingredients by mass percentage: 1-6% copper salt, 1-12% acid, 1-20% organic base and 0.01-5% surfactant, the balance being water; Compared with solution A, solution B has only copper salt replaced by organic acid with corresponding molar content, and the other raw materials are the same, and an organic base is added to adjust the pH to 6.2-6.8.

[0018] In some cases, the copper salt content is preferably 1-4%, which is a combination of inorganic copper salt and organic copper salt in a mass ratio of 1-5:1, preferably 1.5:1-3:1; the inorganic copper salt is one or more of copper chloride, copper sulfate and copper nitrate; the organic copper salt is one or more of copper oxalate, copper tartrate and copper glycinate.

[0019] In some cases, the acid dosage is preferably 2-6%; the acid is a combination of an inorganic acid and an organic acid in a mass ratio of 1-4:1, preferably 2:1-3:1; the inorganic acid is one or more of nitric acid, hypochlorous acid and sulfuric acid; the organic acid is one or more of acetic acid, malonic acid and succinic acid.

[0020] In some cases, the amount of organic base is preferably 5-10%; the organic base is prepared by mixing a pyrazole compound and an amino alcohol compound in a mass ratio of 1 to 5:1.

[0021] In some cases, the dosage of the pyrazole compound is preferably 3-6%; the pyrazole compound is one or more of 3-nitropyrazole, 1,5-dimethylpyrazole and 3-amino-5-hydroxypyrazole.

[0022] In some cases, the amount of the amino alcohol compound is preferably 1-4%; the amino alcohol compound is one or more of 1-amino-2-butanol, 4-dimethylamino-1-butanol and 4-amino-2-methyl-1-butanol.

[0023] In some cases, the amount of surfactant used is preferably 0.05-0.3%; the surfactant is one or more of sodium lauryl polyoxyethylene ether sulfate, tetraethylammonium hydrogen sulfate and tromethamine dodecyl sulfate.

[0024] In some cases, the organic acid is oxalic acid, tartaric acid and / or glycine corresponding to the copper salt.

[0025] The following provides specific examples and comparative examples for detailed description. The specific formula is shown in Table 1, where % is mass percentage.

[0026] Table 1

[0027] When preparing the etching solution in the above embodiments and comparative examples, deionized water is first added, and magnetic stirring is turned on (500r / min), and inorganic acid, organic acid, and copper salt are added in sequence and fully mixed, and then a surfactant is added, and finally an organic base is added, and the temperature of the solution is controlled below 25°C, and the copper etching solution is obtained by mixing (the steps for preparing solution B are the same as those for solution A, and finally an organic base is added to adjust the pH to 6.2 to 6.8).

[0028] The obtained etching solution was used for etching test: Take 1000ml of copper etching solution in a beaker and heat it to stabilize at 35±0.2℃. Then cut the structure to be etched into 20*20mm size and immerse it completely in the etching solution and shake it slightly until the metal copper on the structure is etched away and the structure becomes partially transparent. Record the time required for the structure to become transparent, which is the etching endpoint time, and calculate the etching rate accordingly. Subsequently, gradually add copper powder with a diameter of 80-100nm to the etching solution (add copper powder to dissolve and increase the Cu ion content in the solution to simulate the online etching process), turn on magnetic stirring (speed 500r / min), wait for it to react for 1h, the copper powder in the solution is completely dissolved, and then etch the structure, and record the etching rate and experimental phenomena of the etching solution on copper at different copper ion concentrations. When the Cu ion concentration in solution A reaches 18000ppm, solution B is added to reduce the Cu ion concentration in the copper etching solution to 16000ppm. Then it is etched to 18000ppm, and then solution B is added. This cycle is repeated until the etching solution fails (precipitation occurs in the solution or the etching rate changes by more than 20%) or the cycle exceeds 30 times. The number of cycles in which solution B is updated is recorded.

[0029] The data obtained from the above test are shown in Table 2 below.

[0030] Table 2

[0031] In Comparative Examples 1 and 2, the molar amounts of hydrochloric acid and oxalic acid corresponding to the copper salt in solution B are not the molar amounts of the copper salt in solution A, but are added less or more accordingly, resulting in unstable pH of the etching solution after solution B is added to solution A, and the number of cycles is only 6 and 3 times.

[0032] In Comparative Example 3, the pH of Solution B was adjusted without using an organic base. After Solution B was circulated and renewed 10 times, the etching rate of the solution decreased by more than 20%.

[0033] In Example 4, the content of organic copper salt is too high. When the Cu ion concentration in the etching solution reaches 12000 ppm, dark blue Cu compound crystals are precipitated in the etching solution, and the etching rate increases by more than 20%, and the Cu etching solution becomes ineffective.

[0034] In Example 5, the total content of copper salt is too low. When the Cu ion concentration in the etching solution reaches 7000 ppm, the etching rate of the etching solution increases by more than 20%, and the Cu etching solution becomes ineffective.

[0035] In Example 8, the mass content ratio of organic acid to inorganic acid is 12, and the content of inorganic acid is low. When the Cu ion concentration in the etching solution reaches 13000 ppm, dark blue Cu compound crystals are precipitated in the etching solution, the etching rate increases by more than 20%, and the Cu etching solution fails.

[0036] In Example 9, the mass content ratio of organic acid to inorganic acid is 1, and the content of organic acid and inorganic acid is low. When the Cu ion concentration in the etching solution reaches 5000ppm, the etching rate increases by more than 20%, and the Cu etching solution becomes ineffective.

[0037] In Example 12, the ratio of pyrazole to amino alcohol compounds is 6, and the pyrazole content is relatively high. When the Cu ion concentration in the etching solution reaches 14000 ppm, dark blue Cu compounds crystallize out in the etching solution, the etching rate increases by more than 20%, and the Cu etching solution becomes ineffective.

[0038] In Example 13, the ratio of pyrazole to amino alcohol compound is 0.5. When the Cu ion concentration in the etching solution reaches 6000 ppm, dark blue Cu compound crystals are precipitated in the etching solution, the etching rate increases by more than 20%, and the Cu etching solution becomes ineffective.

[0039] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A long-life dual-type copper etching solution, characterized in that: The etching solution includes liquid A and liquid B; Liquid A contains the following ingredients by mass percentage: 1-6% copper salt, 1-12% acid, 1-20% organic base and 0.01-5% surfactant, the balance being water; Compared with solution A, solution B only replaces copper salt with organic acid of corresponding molar content, and the other raw materials are the same, and an organic base is added to adjust the pH to 6.2-6.8; During the etching process, only liquid A is used first. When the etching life of liquid A reaches its limit, liquid B is repeatedly added to extend its etching life.

2. The long-life dual-type copper etching solution according to claim 1, characterized in that: The copper salt is a combination of an inorganic copper salt and an organic copper salt in a mass ratio of 1-5:1; the inorganic copper salt is one or more of copper chloride, copper sulfate and copper nitrate; the organic copper salt is one or more of copper oxalate, copper tartrate and copper glycinate.

3. The long-life dual-type copper etching solution according to claim 1, characterized in that: The acid is a combination of an inorganic acid and an organic acid in a mass ratio of 1 to 4:1; the inorganic acid is one or more of nitric acid, hypochlorous acid and sulfuric acid, and the organic acid is one or more of acetic acid, malonic acid and succinic acid.

4. The long-life dual-type copper etching solution according to claim 1, characterized in that: The organic base is a combination of a pyrazole compound and an amino alcohol compound in a mass ratio of 1 to 4:

1.

5. The long-life dual-type copper etching solution according to claim 4, characterized in that: The pyrazole compound is one or more of 3-nitropyrazole, 1,5-dimethylpyrazole, and 3-amino-5-hydroxypyrazole.

6. The long-life dual-type copper etching solution according to claim 4, characterized in that: The amino alcohol compound is one or more of 1-amino-2-butanol, 4-dimethylamino-1-butanol and 4-amino-2-methyl-1-butanol.

7. The dual-component copper etching solution according to any one of claim 1, characterized in that: The surfactant is one or more of sodium lauryl polyoxyethylene ether sulfate, tetraethylammonium hydrogen sulfate and tromethamine dodecyl sulfate.

8. The dual-component copper etching solution according to any one of claims 1 to 7, characterized in that: The organic acid is oxalic acid, tartaric acid and / or glycine corresponding to the copper salt.

9. The dual-component copper etching solution according to any one of claims 1 to 7, characterized in that: When the Cu ion concentration of solution A reaches 18000ppm, solution B is added to adjust the Cu ion concentration in the copper etching solution to 16000-18000ppm.

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